Biological processes affected in the bipolar orbitofrontal cortex. Biological processes specifically enriched among the 238 upregulated transcripts and the 155 downregulated transcripts in bipolar disorder were identified and visualised using GoSurfer (http://biosun1.harvard.edu/complab/gosurfer/). In the hierarchical tree, the nodes represent individual GO biological process categories and the branches indicate the relationships between them. GO categories containing more than 12 genes are shown. Significantly altered processes (P<0.01) are highlighted: red indicating specific upregulation of a GO category and blue indicating specific down-regulation of a GO category. Numbers refer to the GO category names listed below, which are divided into the four major pathways dysregulated in bipolar disorder. Note: the GO categories 'nuclear transport' and 'nucleocytoplasmic transport' were significant at P<0.01 but are not shown as they contained less than 12 genes. Abbreviations: GPCR, G-protein coupled receptor; GO, gene ontology.